document.write( "Question 310853: Solve the trig equation sin2x = sqrt(3)sinx \n" ); document.write( "
Algebra.Com's Answer #225711 by J2R2R(94) You can put this solution on YOUR website! Solve the trig equation sin(2x) = sqrt(3)sin(x)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "sin(2x) = 2 sin(x) cos(x)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So we have\r \n" ); document.write( "\n" ); document.write( "2 sin(x) cos(x) = sqrt(3) sin(x)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We can cancel sin(x) from both sides which makes sin(x) = 0 a solution i.e. 0, 180, 360, etc.\r \n" ); document.write( "\n" ); document.write( "2 cos(x) = sqrt(3) or cos(x) = sqrt(3)/2 giving x=30 and 330.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So solutions in degrees in the range 0<=x<360 are\r \n" ); document.write( "\n" ); document.write( "0, 30, 180 and 330\r \n" ); document.write( "\n" ); document.write( "which shows there are four solutions for each 360 degrees range.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "N.B. bear in mind that a 360 degree range does not take both end points in its range since one end point is the other end point with 360 added to it. \n" ); document.write( " |